@article {47754,
	title = {In-situ experimental and computational approach to investigate the nature of active site in low-temperature CO-PROX over CuOx-CeO2 catalyst},
	journal = {Applied Catalysis A-General},
	volume = {624},
	year = {2021},
	month = {AUG },
	pages = {118305},
	type = {Article},
	abstract = {Preferential oxidation (PROX) of carbon monoxide (CO) in presence of excess hydrogen is a necessity to prevent poisoning of the Pt-anode by CO in PEMFCs (Polymer Electrolyte Membrane Fuel Cell). A highly active catalyst, 5 wt\% Cu-CeO2 showed 100 \% CO conversion at 65 degrees C without any undesirable oxidation of H-2. The catalyst showed no deactivation even after 100 h on stream, making it viable for practical fuel cell application. Operando EPR in the PROX reaction condition revealed highly dispersed mixed valent cations with oxygen vacancies, responsible for the low-temperature PROX activity. At the active site, both Cu and Ce ions were shown to reversibly change their valence states to facilitate the abstraction of bridging lattice oxygen for CO oxidation to CO2. This surface oxygen mediated CO oxidation was found to be much faster than that of H-2 to H2O, which could explain the complete selectivity of oxygen for CO2 formation.},
	keywords = {CuOx-CeO2, interface, Oxygen vacancy, PROX, Synergistic},
	issn = {0926-860X},
	doi = {10.1016/j.apcata.2021.118305},
	author = {Adak, Shubhadeep and Rabeah, Jabor and Ranjan, Ravi and Khan, Tuhin Suvra and Poddar, Mukesh Kumar and Gupta, Rishi Kumar and Sasaki, Takehiko and Kumar, Sagar and Bordoloi, Ankur and Gopinath, Chinnakonda S. and Bruckner, Angelika and Bal, Rajaram}
}
@article {48218,
	title = {Boosting electrochemical CO2 reduction to methane via tuning oxygen vacancy concentration and surface termination on a copper/ceria catalyst},
	journal = {ACS Catalysis},
	volume = {12},
	year = {2022},
	month = {SEP},
	pages = {10973-10983},
	type = {Article},
	abstract = {<p>
	Metal oxides are a promising material for designing highly active and selective catalysts for the electrochemical reduction of carbon dioxide (CO2RR). Here, we designed a Cu/ceria catalyst with high selectivity of methane production at single-atomic Cu active sites. Using this, we report favorable design concepts that push the product selectivity of methane formation by combining detailed structural analysis, density functional theory (DFT), in situ Raman spectroscopy, and electrochemical measurements. We demonstrate that a higher concentration of oxygen vacancies on the catalyst surface, resulting from more available Cu+ sites, enables high selectivity for methane formation during CO2RR and can be controlled by the calcination temperature. The DFT calculation and in situ Raman studies indicate that pH controls the surface termination; a more alkaline pH generates hydroxylated surface motifs with more active sites for the hydrogen evolution reaction. These findings provide insights into designing an efficient metal oxide electrocatalyst by controlling the atomic structure via the reaction environment and synthesis conditions.</p>
},
	keywords = {copper-ceria, electrochemical CO2 reduction, electrolyte pH, gas diffusion electrode, methane production, Oxygen vacancy},
	issn = {2155-5435},
	doi = {10.1021/acscatal.2c02669},
	author = {Patra, Kshirodra Kumar and Liu, Zhu and Lee, Hojeong and Hong, Seungwon and Song, Hakhyeon and Abbas, Hafiz Ghulam and Kwon, Youngkook and Ringe, Stefan and Oh, Jihun}
}
@article {48000,
	title = {Sustainable CO2 reduction on in (2)O(3 )with exclusive CO selectivity: catalysis and in situ valence band photoelectron spectral investigations},
	journal = {ACS Sustainable Chemistry \& Engineering},
	volume = {10},
	year = {2022},
	month = {MAR},
	pages = {3521-3531},
	type = {Article},
	abstract = {<p>
	This study demonstrates a sustainable catalytic CO2 conversion to near 100\% CO selectivity at ambient pressure on In2O3. Critically, high CO yield could be observed at the cost of undesired methanation, using a lower than stoichiometric amount of hydrogen in the feed; 1:1 and 1:0.67 CO2:H-2 ratios exhibit 98-99.6\% CO selectivity with 25-38\% CO2 conversion between 773 and 873 K. CO2 and H-2 conversion under steady-state conditions at 773-873 K suggests a 1:1 ratio of adsorbed reactants (with 1:0.67 CO2:H-2 feed) on the catalyst surface, underscoring the presence of an ideal reactant composition for the reverse water-gas shift reaction, while H-2-rich feed compositions show the H-2-dominated surface. Surface electronic structure changes, under near-operating conditions, were explored with near ambient pressure photoelectron spectroscopy (NAPPES), and the interesting findings are as follows: (a) A shift in the valence band to lower binding energy, up to 0.6 eV, was observed because of electron filling at high temperatures. (b) An observation of heterogeneous nature of the catalyst surface under NAPPES measurement conditions is attributed to the generation of active oxygen vacancy (O-v) sites, which in turn changes the work function of In2O3. (c) The above changes are found to be reversible, when the reaction was stopped. Vibrational features of the reactant molecules were observed to be broadened in the active temperature window of the catalyst supporting the heterogeneous character of the catalyst surface because of dynamic O-v generation. By optimizing gas hourly space velocity, CO2:H-2 ratio, and reaction temperature, exclusive CO selectivity is possible with a H-2:CO2 ratio of similar to 0.67, which will avoid the product separation stage altogether, while minimizing the expensive H-2 in the reactant feed.</p>
},
	keywords = {heterogeneous catalysis, Oxygen vacancy, photoelectron spectroscopy, RWGS, Work function},
	issn = {2168-0485},
	doi = {10.1021/acssuschemeng.1c07897},
	author = {Mhamane, Nitin B. and Chetry, Sibo and Ranjan, Ravi and Raja, Thirumalaiswamy and Gopinath, Chinnakonda S.}
}
